The present invention relates to a semiconductor device capable of determining a moving state of a user who possesses an electrical terminal according to an input signal from, for example, an acceleration sensor.
In a conventional technique, an acceleration sensor is used for determining a moving state of a user. More specifically, the acceleration sensor is attached to the user, so that data can be retrieved from the acceleration sensor. According to the data, a variation in acceleration that is characteristic to a specific moving state is detected, so that the moving state of the user is determined (refer to Patent Reference).
Patent Reference: Japanese Patent Publication No. 2011-30643
In recent years, in a conventional electrical terminal such as a smart phone, in order to reduce power consumption of a data processing processor, it has been required to change the data processing processor to a terminated state (a suspended state) when the data processing processor is not conducting a data processing. However, in order to determine the moving state of the user regularly, it is necessary to continue to retrieve information from the acceleration sensor all the time. In this case, it is difficult to put the data processing processor in the suspended state, thereby making it difficult to reduce the power consumption of the data processing processor.
To this end, in addition to the data processing processor to be used for performing a normal processing of the conventional electrical terminal, a sub-processor (a micro-controller) with low power consumption is provided as another processor for retrieving the information from the acceleration sensor. Accordingly, the sub-processor is configured to control the acceleration sensor, thereby making it possible to reduce the power consumption of the conventional electrical terminal.
In the conventional electrical terminal, however, when the sub-processor with the low power consumption is provided, data processing performance thereof tends to be lowered. Accordingly, when the moving state of the user is determined, it is difficult to process an amount of data similar to that of the data processing processor. As a result, it is necessary to determine the moving state of the user using a limited amount of data within a limited period of processing time. Further, it is difficult to improve determination accuracy through using a sensor with large power consumption or a plurality of sensors.
In view of the problems of the conventional technique described above, an object of the present invention is to provide a semiconductor device capable of solving the problems of the conventional semiconductor device. In the present invention, it is possible to accurately determine the moving state of the user even when the semiconductor device is provided with a main processor for performing a normal data processing to realize a function of an electrical terminal and a sub-processor with lower power consumption that that of the main processor for controlling a sensor.
Further objects and advantages of the invention will be apparent from the following description of the invention.